Schedule 7A 


December 20, 1920 


DEPARTMENT OF THE INTERIOR 

JOHN BARTON PAYNE, Secretary 

14. S BUREAU OF MINES 

*» . 

H. FOSTER BAIN, Acting Director 


PROCEDURE FOR ESTABLISHING A 
LIST OF PERMISSIBLE MINERS’ FLAME 

SAFETY LAMPS 

CHARACTER OF TESTS, CONDITIONS UNDER 
WHICH LAMPS WILL BE TESTED, AND FEES 



2_ ( - fc I"?' £ 


WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1921 

Co??pcted set* 



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The Bureau of Mines, in carrying out one of the provisions of its organic 
act—to disseminate information concerning investigations made—prints a 
limited free edition of each of its publications. 

When this edition is exhausted, copies may be obtained at cost price only 
through the Superintendent of Documents, Government Printing Office, Wash¬ 
ington, D. C. 

The Superintendent of Documents is not an official of the Bureau of Mines. 
His is an entirely separate office, and he should be addressed: 

Superintendent of Documents, 

Government Printing Office, 

Washington, D. C. 

The general law under which publications are distributed prohibits the 
giving of more than one copy of a publication to one person. The price of this 
publication is 5 cents. 


2 


First edition, February, 1921 . 


LIBRARY OF CONGRESS 

RECEIVED 

MARI-1921 

DOCUMENTS DIVISION 





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CONTENTS. 

Page. 


Preliminary statement_ 5 

Authorization_ 5 

Definition of permissible_ 5 

Conditions under which flame safety lamps will be tested_ 5 

General requirements for lamps_ 6 

Character of tests_ 8 

Mechanical tests using a complete lamp_ 8 

Details of tests_ 8 

Tests of lamp glasses_ 9 

Details of tests_ 9 

Tests to determine the mean zonal candlepower of the lamp_ 10 

Tests to determine the safety of the lamp in explosive mixtures_ 10 

Igniter tests_ 11 

Properties of gas used in the tests_ 11 

Approval of permissible miners’ safety lamps_ 11 

Notification of manufacturer- 11 

Scope of approval_ 11 

Approval plate_1_ 12 

Withdrawal of approval- 12 

Fees for testing flame safety lamps- 12 

Remittances_ 13 

Synopsis of procedure to be followed in making application for tests, sub¬ 
mitting material, conducting tests, and notifying applicant of results— 13 
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PROCEDURE FOR ESTABLISHING A LIST OF PERMISSIBLE MINERS’ SAFETY LAMPS: 
CHARACTER OF TESTS, CONDITIONS UNDER WHICH LAMPS WILL BE TESTED, 
AND FEES. 


PRELIMINARY STATEMENT. 

AUTHORIZATION. 

An act of Congress (37 Stat., 681) approved February 25, 1913, 
contains the following provision in regard to tests or investigations 
performed by the Bureau of Mines: 

That for tests or investigations authorized by the Secretary of the Interior 
under the provisions of this act, other than those performed by the Government 
of the United States, or State governments within the United States, a rea¬ 
sonable fee covering the necessary expenses shall be charged, according to a 
schedule prepared by the Director of the Bureau of Mines, and approved by 
the Secretary of the Interior, who shall prescribe rules and regulations under 
which such tests or investigations may be made. All moneys received from 
such sources shall be paid into the Treasury to the credit of miscellaneous 
receipts. 

The Bureau of Mines is prepared, at its Pittsburgh experiment 
station, to conduct tests of miners’ flame safety lamps for the pur¬ 
pose of establishing a list of permissible safety lamps for use in 
gaseous mines. This schedule of tests is issued for the information 
of those who may desire to submit equipment for test. It supersedes 
schedule No. 7, issued under date of January 30, 1915, and goes into 
effect on the date of its approval by the Secretary. 

DEFINITION OF PERMISSIBLE. 

The Bureau of Mines considers a miners’ flame safety lamp to be 
permissible for use in gaseous mines if the details of the construction 
of the lamp are the same in all respects as those tested and approved 
by the bureau in accordance with this schedule. 

CONDITIONS UNDER WHICH FLAME SAFETY LAMPS WILL BE 

TESTED. 

The conditions under which the Bureau of Mines will examine 
and test miners’ flame safety lamps to establish their permissibility 
are as follows: 

1. The tests will be made at the experiment station of the Bureau 
of Mines, at Pittsburgh, Pa. 


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6 


PERMISSIBLE MINERS’ ELAME SAFETY LAMPS. 


2. Applications for tests shall be addressed to the Director, Bureau 
of Mines, Washington, D. C., and shall be accompanied by a com¬ 
plete description of the lamp to be tested and a full set of the 
drawings mentioned below: 

A drawing or drawings clearly showing the character, size, and 
relative arrangement of the lamp parts. The drawing or drawings 
shall specify the material of which all parts are made. 

Any other drawings necessary to identify or explain any feature 
tliat is to be considered in the approval of the lamp or its acces¬ 
sories. 

A copy of the description, a duplicate set of the drawings, and one 
complete lamp shall be sent to the electrical engineer, Bureau of 
Mines, 4800 Forbes Street, Pittsburgh, Pa. 

3. As soon as possible after receipt of his application for test the 
manufacturer will be notified as to the date on which his equipment 
will be tested and the amount of any additional material that it will 
be necessary for him to submit. 

4. The manufacturer shall deliver to the Bureau of Mines, 4800 
Forbes Street, Pittsburgh, Pa., two weeks prior to the date set for 
the test, the necessary parts for determining the permissibilit}^ of 
his lamp. 

5. No one is to be present during the permissibility tests except 
the necessary Government officers at the experiment station, their 
assistants, representatives of the manufacturer of the lamp under 
test, and such other persons as may be mutually agreed upon by the 
manufacturer and the bureau. 

6. Permissibility tests of flame safety lamps will not be made 
unless the lamps have been completely developed and are in a form 
in which they may be put on the market. 

7. Tests will be made in the order of the receipt of application 
for them, provided that the necessary material is submitted at the 
proper time. 

8. The details of the results of the tests shall be regarded as con¬ 
fidential by all present at the tests and shall not be made public 
in any way prior to the formal approval of the lamp by the Bureau 
of Mines. 

GENERAL REQUIREMENTS FOR LAMPS. 

1. None but bonneted lamps will be tested for permissibility. 

2. Gauzes shall be made of steel, charcoal-annealed iron, or other 
suitable material which will pass the tests devised to determine the 
safety and practicability of the gauze material. 

The gauze wire shall not be larger than No. 27 nor smaller than 
No. 29 American wire gage. 


PERMISSIBLE MINERS 7 FLAME SAFETY LAMPS. 7 

The gauze wires shall be evenly spaced not less than 28 per linear 
inch. If No. 29 (A. W. G.) wire is used there shall be at least 30 
wires per linear inch. 

The fabrication into gauzes shall be effected so that there shall be 
no material distortion of the gauze fabric. The engineers in charge 
of the tests shall decide whether or not sufficient distortion exists to 
affect the safety of the lamp. 

3. If lamp standards are used, a straight line touching the exterior 
part of any two consecutive standards shall not touch the glass. 

4. The lamp shall be so constructed that it will not be possible 
without easy detection to assemble the component parts of the lamp 
without the gauzes. 

5. The lamp shall be provided with an effective magnetic locking 
device to prevent the fuel vessel, glass, or gauzes from being re¬ 
moved or from being loosened to such an extent that the safety of 
the lamp is impaired while the lamp is in the locked condition. Pro¬ 
vision shall also be made for taking up the play due to wear of the 
screw threads. 

6. The glasses shall have smooth surfaces throughout. They 
should have their ends ground parallel and at right angles to the 
axis of the glass. 

The maximum allowable deviation in the distance between the 
ends of the glass measured at any two places shall be 0.01 inch. 

The glasses shall be as nearly uniform in thickness as it is prac¬ 
ticable to make them. 

7. The glass shall be distinctly and permanently marked by a 
name or design by which its type is designated for trade purposes. 

8. The lamp shall burn for at least 12 hours with flame adjusted* 
to a height of 1 inch. 

9. The lamp, fully assembled, shall give an average mean zonal 
candlepower 1 of at least 0.3 throughout a period of 10 hours, during 
which the height of the flame is 1 inch. 

10. The angle of the light zone shall be not less than 90°, measured 
when the height of the flame is 1 inch. 

11. The lamp shall develop a well-defined gas cap in a gas and 
air mixture of 2 per cent gas. Observation shall be made by at 
least three persons in a totally dark inclosure. 

12. The lamp shall not be extinguished when let swing through 
an arc of 35° against a wood bumper, when the length of the radius 
from the point of support to the bottom of the lamp is 7 feet. The 
height of the wick flame shall be 1 inch for this test. 

13. Lamps will be examined with special reference to the mechani¬ 

cal construction, size, weight, replacement of parts, ease of inspec¬ 
tion, and attention required. _ 


1 As defined in the standardization rules of the A. I. E. E 





8 


PERMISSIBLE MINERS’ FLAME SAFETY LAMPS. 


CHARACTER OF TESTS. 

MECHANICAL TESTS USING A COMPLETE LAMP. 

Tests to determine the security of the lamp as an assembled unit 
and the durability of the lamp glasses under severe conditions shall 
be made under the following conditions: 1. Dropping the lamp it¬ 
self. 2. Dropping a weight upon the lamp. 3. Dropping a weight at¬ 
tached to the bottom of the lamp (the lamp being suspended). 

DETAILS OF TESTS. 

1. Dropping the lamp. —This test shall consist of five trials in 
which a completely assembled lamp is dropped onto a wood floor. 
The lamp shall be suspended at a height of 6 feet, measured from the 
floor to the bottom of the lamp, and then released by mechanical 
means. The lamp shall be fitted with a new glass before each trial. 

This test is devised to show the durability of the glass in case of 
accident or in case of rough handling of the lamp. Therefore, if the 
glass is broken in not more than one trial, the lamp glasses will be 
considered satisfactory. If the glass is broken in more than one trial, 
the lamp glasses will be considered unsatisfactory. However, if the 
glass is broken in two but not more than two of the five trials, a re¬ 
test of five trials will be made. If more than one glass is broken in 
the retest the lamp glasses will fail to pass the test. 

2. Dropping a weight upon lamp. —This test shall consist of a 
single trial in which a 5-pound weight is dropped upon a completely 
assembled lamp. The lamp shall be placed in a vertical position upon 
a wood floor and a lead weight (3 inches in diameter and 1} inches 
thick) shall be suspended directly over the lamp at a height of 6 
feet, measured from the top of the lamp to the bottom of the weight. 
The weight shall be released mechanicallv. 

This test is devised to show the ability of the lamp framework to 
withstand impact blows such as might result from falling rock. There¬ 
fore, if the framework is materially distorted, the lamp will fail to 
pass the tests. Also, if the lamp glass is broken, in this test, and in a 
retest made under identical conditions, the lamp glasses will be con¬ 
sidered unsatisfactory. 

3. Dropping weight attached to bottom of the lamp. —This test 
shall consist of three trials in which a 10-pound weight is attached to 
a suspended lamp. The lamp shall be held in position by a clamp 
around its upper part, and the weight shall be attached by means of a 
second clamp and wire rope to the bottom part of the lamp. The 
weight is then raised after which it is released mechanically in such 
a manner as to permit it to fall through a distance of 6 feet (at which 
point the rope is taut) giving a sudden jerking force to the lamp. 


PERMISSIBLE MINERS ’ FLAME SAFETY LAMPS. 9 

This test is devised to show the security of the framework of the 
lamp, especially the lamp standards. Therefore, if, as a result of 
any of the three trials, the standard or other parts become so 
loosened, weakened, or otherwise distorted as to affect the safety of 
the lamp, the framework of the lamp will be considered unsatisfac¬ 
tory and the lamp will fail to pass the test. 

The mechanical tests shall all be made with the same lamp. The 
engineer in charge of the tests shall decide whether or not sufficient 
distortion resulted to affect the safety of the lamp. A lamp that has 
successfully passed the mechanical tests shall be reassembled and 
subjected to at least three trials in moving explosive mixtures of 
Pittsburgh natural gas and air. These trials may be made either 
before or after the regular tests in gas and under such conditions 
as the engineer in charge of the tests shall judge most likely to prove 
the safety of the lamp. 

The term u broken glass ” wherever used in this schedule shall be 
interpreted to mean a glass having any of the following defects: (a) 
Three or more, cracks; (b) one or more spalls or chipped places 
which include more than two-thirds of the thickness of the glass; 

(c) one or more cracks which extend the entire length of the glass; 

(d) two or more cracks which include an area. 

TESTS OF LAMP GLASSES. 

In addition to tests in the assembled lamp, glasses submitted for 
use with a lamp shall be tested separately for durability under the 
following conditions: 1. Dropping a weight upon the glass. 2. Spray¬ 
ing heated glasses with cold water. 

DETAILS OF TEST. 

1. Dropping a weight upon the glasses .—This test shall consist oi 
20 trials (one for each of 20 glasses), in which a 1-pound lead weight 
is dropped upon a glass. The glass shall be placed vertically on a 
wood floor and a lead weight (2J inches in diameter and \ inch 
thick) shall be suspended directly over the glass at a height of 4 
feet, measured from the top of the glass to the bottom of the weight. 
The weight shall be guided in its fall by a mechanical arrangement 
in order that the end of the glass will be hit squarely. 

If two or more glasses are broken they will fail to pass the test and 

will be rejected without further tests. 

2. Spraying' heated glasses .—This test shall consist of subjecting 
50 glasses to a water spray after they have been heated to a pre¬ 
determined temperature. The glasses will be tested in groups of 10. 
The glasses shall be heated to a temperature of 212° F. and then 
sprayed with water ranging from 60° to 65° F. 


10 PERMISSIBLE MINERS’ FLAME SAFETY LAMPS. 

If five or more glasses are broken as a result of this test, the glasses 
will fail to pass the test. 

TESTS TO DETERMINE THE MEAN ZONAL CANDLEPOWER OF THE LAMP. 

At least three lamps shall be tested for candlepower and the aver¬ 
age result taken as the true performance of the lamp. Pach lamp 
shall be placed in a photometric cube and compared with a specially 
made standard electric lamp. 

The lamp shall have been burning for at least one-lialf hour before 
the start of the test and the flame height shall be maintained at 1 
inch throughout the test. 

The height of the flame shall be measured from the tip of the 
luminous flame to the top of the wick holder. 

The fuel used shall be that which the manufacturer supplies for 
use with his lamp. This fuel should be identified by specifications. 

The angle of the light zone shall be the angle between the extreme 
light rays from the upper and the lower parts of the wick flame. 

TESTS TO DETERMINE THE SAFETY OF THE LAMP IN EXPLOSIVE MIXTURES. 

Completely assembled, lighted lamps shall be tested in moving 
mixtures of Pittsburgh natural gas and air as follows: 

Horizontal currents (Gallery 6). —Tests in 6, 8.6, and 11 per cent 
gas mixtures at velocities of 600, 800, 1,000, 1,200, 1,500, 2,000, and 

2.500 feet per minute. Three trials shall be made under each com¬ 
bination of gas percentage and velocity (two trials of two minutes’ 
duration and one trial of five minutes’ duration). Coal dust shall be 
mixed with the gaseous mixture during the last minute of each five- 
minute trial. At the end of every trial the gas valve shall be closed 
>ery slowly, other settings remaining untouched until the gas valve 
is closed. 

Into a horizontal current of 8.6 per cent gas mixture moving at 

1.500 feet per minute the lighted lamp will be suddenly thrust from 
below. Three trials. 

Vertical ascending , vertical descending , 45° ascending , and 45° de¬ 
scending currents (Gallery 6 ).—One to three trials of two minutes’ 
duration in an 8.6 per cent gas mixture at 600, 1,000, 1,500, and 2,500 
feet per minute velocity shall be made for each direction of current. 

Still, gaseous mixture (Gallery 3). —A completely assembled 
lighted lamp shall be placed in an 8.6 per cent mixture of natural 
gas and air for five minutes. Three trials. (This test need not be 
made upon lamps which are tested in connection with 1 igniters.) 

In all of the tests in gaseous mixtures the lamp will be fitted with 
new gauzes for every trial if the preceding trial has oxidized or 
otherwise noticeably changed the surface of the gauze. 

An explosion exterior to the lamp in any of these tests will cause 
tire lamp to be rejected. 


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PERMISSIBLE MINERS’ ELAME SAFETY LAMPS. 


IGNITER TESTS. 


Lamps having igniters will be tested to determine the safety and 
permissibility of the igniter device. 

These tests will be made: 

1. To determine if external ignition is possible when the igniter is 
operated in still and in moving currents of gas and air mixtures. 

2. To determine if the residue left in the lamp after working the 
igniter device is a source of danger in the subsequent use of the lamp 
in inflammable mixtures of gas and air. 

3. To determine the nature of the material used in the igniter de¬ 
vice. 

The igniter will have passed the tests if no external ignition is 
caused by manipulating the igniter when in position within the lamp, 
or if no external ignition is caused by the use of the lamp in inflam¬ 
mable mixtures of gas and air after the igniter has been in service. 

Applicants for tests will be required to furnish two complete 
igniter devices and five dozen igniter refills, which shall be shipped in 
sealed boxes or packages with the trade name written on the outside 
and addressed to the electrical engineer, Bureau of Mines, 4800 
Forbes Street, Pittsburgh, Pa. The approximate chemical compo¬ 
sition of the igniter tape or point and the name of the manufacturer 
shall be furnished. 

PROPERTIES OF GAS USED IN THE TESTS. 

The inflammable gas used in these series of tests will be the natural 
gas supplied to the city of Pittsburgh. 

APPROVAL OF PERMISSIBLE MINERS’ SAFETY LAMPS. 

NOTIFICATION OF MANUFACTURER. 

When the bureau’s engineers are satisfied that a lamp is permis¬ 
sible, the manufacturer, agent or applicant, and the mine inspection 
departments of the several States shall be notified to that effect. As 
soon as a manufacturer receives formal notification that his lamp has 
passed the tests prescribed by the Bureau of Mines, he shall be free 
to advertise such lamp as permissible. 

SCOPE OF APPROVAL. 

The bureau’s approval of any flame lamp shall be construed as ap¬ 
plying to all lamps of the same manufacturer that have the same con¬ 
struction as the lamps tested and approved by the bureau, but to no 
other lamps. The manufacturer shall, before claiming the bureau’s 
approval for any modification of his approved lamp, submit to the 
* bureau drawings that shall show the extent and nature of such modi¬ 
fication in order that the bureau may decide whether or not it should 


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PERMISSIBLE MINERS ’ FLAME SAFETY LAMPS. 


test the remodeled lamp before approving it. Each approval of a 
permissible flame safety lamp will be given a serial number. Ap¬ 
provals of modified forms of a previously approved lamp will bear 
the same number as the original approval with the addition of the 
letters a, b, c, etc. 

APPROVAL PLATE. 

The manufacturer will be required to attach to the lamp a plate 
bearing the seal of the Bureau of Mines and inscribed as follows: 


PERMISSIBLE MINERS’ FLAME SAFETY LAMP. 
ISSUED FOR SAFETY, DURABILITY, AND EFFICIENCY TO THE 

__ COMPANY. 

APPROVAL NO._ 


An attached approval plate will not be required when the seal 
and inscription can be satisfactorily stamped into the lamp? 

WITHDRAWAL OF APPROVAL. 

The bureau reserves the right to rescind, for cause, at any time, 
any approval granted under the conditions herein set forth. 

FEES FOR TESTING FLAME SAFETY LAMPS. 


The following fees, to be charged on and after the date of ap¬ 
proval of this schedule, have been established and approved by the 
Secretary of the Interior: 

Item 1. Lamp with igniter .—For a complete official investigation of a 

lamp which is equipped with an igniter_$150. 00 

Item 2. Lamp without igniter .—For a complete official investigation of 

a lamp which is not equipped with an igniter_ 100. 00 

Item 3. Segregated charges — 

Preliminary inspection_ 5. 00 

Tests to determine the mechanical strength of the lamp_ 5. 00 

Tests to determine the mechanical strength of the glasses_ 5. 00 

Temperature test of glasses_ 10.00 

Tests to determine the safety of the lamp in explosive mixtures_ 50. 00 

Tests to determine the mean zonal candlepower and time of burn¬ 
ing of the lamp- 20. 00 

Final inspection_ 5. 00 

Igniter tests-1_ 50. 00 


150. 00 

Item 4. Special tests .—Special tests to assist the manufacturer in the 
development of equipment will be made at his request and will be 
charged for in accordance with the work involved. Each request for 
special tests should be accompanied by a fee of $100 made payable to 
the Secretary of the Interior. Any unused moneys from such deposit 
will be refunded at the completion of the special tests on request by 
the manufacturer. 















PERMISSIBLE MINERS’ FLAME SAFETY LAMPS. 


13 


REMITTANCES. 

Manufacturers who submit lamps for tests to determine permis¬ 
sibility for use in gaseous mines will be required to furnish a cer¬ 
tified check or bank draft that shall cover the total fees required for 
the tests and shall be made payable to the Secretary of the Interior. 
Such fees shall be received at least one week prior to the date set 
for beginning the tests; otherwise the equipment of the next appli¬ 
cant on the list will be tested. 

SYNOPSIS OF PROCEDURE TO BE FOLLOWED IN MAKING APPLICA¬ 
TION FOR TESTS, SUBMITTING MATERIAL, CONDUCTING TESTS, 

AND NOTIFYING APPLICANT OF RESULTS. 

1. Application for tests should be addressed to the Director of 
the Bureau of Mines, Washington, D. C. The application should 
be accompanied by a check or draft and by a complete description 
of the lamp to be tested and a set of the drawings described under 
“ Conditions for Tests.” Duplicate copies of the application, de¬ 
scription, ‘ and drawings should be sent to the electrical engineer, 
Bureau of Mines, 4800 Forbes Street, Pittsburgh, Pa., accompanied 
by a complete lamp. 

2. As soon as the application has been reviewed by the bureau’s 
engineers the applicant will be notified of the date of the test and 
the number of lamp parts and accessories that it will be necessary 
for him to submit. 

3. After receiving this notification the applicant should send the 
material required to the electrical engineer, Bureau of Mines, 4800 
Forbes Street, Pittsburgh, Pa. This material should be delivered 
not less than two weeks in advance of the date set for the beginning 
of the tests. At this time the applicant should state the name and 
address of the applicant's representative who will witness the tests. 

4. The tests will be begun on the date set and continued until the 
lamp is approved, rejected, or withdrawn. In case the lamp is 
withdrawn by the manufacturer before an investigation has been 
completed, fees will be charged in accordance with the work per¬ 
formed up to the time of withdrawal. Any surplus funds over and 
above those covering the tests made will be refunded upon due noti¬ 
fication by the manufacturer that no more tests are contemplated. 

5. After the bureau’s engineers have considered the result of the 
tests, a formal report of the approval or disapproval of the lamp 
will be made to the applicant in writing by the Director of the 
Bureau of Mines. No verbal report will be made, and the details of 
the tests must be regarded as confidential by all present. 

F. G. Cottrell, 

Director . 

Approved, December 20, 1920. 

John Barton Payne, 

Secretary . 

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